Bringing up a PX4 on a FlameWheel F330

I recently got a PX4FMU plus PX4IO board kit and I am installing it on my little DJI Flamewheel F330 that I had been using previously with my APM 2.


The F330 is a perfect candidate for this because it is an excellent and sturdy test bed.

It flew very well with my APM 2.

Previously I was using An Oring suspension mount on the 4 standoffs you can see in the photo above.

This time I decided to try mounting the PX4 stack on a thin fiberglass plate plate which is mounted on some 1/2" pads of Kyosho Zeal anti vibration gel. 


The PX4 stack is already pretty high so I thought I'd try this before using both the Zeal and the O-ring mount I had planned.


The Zeal Gel which comes with double sided tape on both sides is almost a quarter inch thick and it seems appropriately flexible and vibration absorbent in this application with the four 1/2" square pads.

The Accel readings will tell the tale.

Note that the inter board connector on the left is about 2mm  shy of closing. 

3DR supplies 8mm M3 standoffs and I think that 6 mm ones would work better, although their would be a slight interference fit at the other end of the board.


Notice all the stuff still hanging off of it.

The GPS, the arming switch, the buzzer and the battery power leads for the PX4's built in power supply.

Still have to figure out where to stick all this stuff on my little Flamewheel.

I have already installed the firmware and bench tested this PX4FMU plus PX4IO stack. 

The PX4 stack is upside down from normal spec, but it makes the connectors easier to get at and it is easy to do with the new Mission Planner adjustable Board Orientation parameter.

I will also be attempting to use one of the little 3DR Receiver servo to PPM-Sum out converters, so this promises to be an interesting adventure.

I will keep everybody posted and new pics as this build - test continues.

Please feel free to post comments and questions.

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  • I have found a few things that might be useful re the PX4.

    My USB power will not provide sufficient voltage to power the receiver and the 8 channel encoder and the PX4, PX4 works fine, but receiver will not bind with transmitter and indicates not bound, in fact if you plug in the battery for the Transmitter Configuration portion of setup and leave it disconnected for everything else it works fine.

    Another thing that drove me nuts for almost an hour is that all at once it wouldn't connect.

    Hint! - it is really easy to bump the MicroSD card on the PX4FMU and have it released but still in the holder. It does not work well in this mode however.

    I am running mine upside down (advanced param AHRSBOARD_ORIENTATION (roll 180) (number 8 I think).

    So the PX4FMU is on the bottom and it is not easy to see the status of the SD card.

  • Hi all, Flew my F330 Flamewheel with PX4FMU and PX4IO mounted on 4 Kyosho Zeal pads and got this really excellent Accel graph.

    Plus and minus one = 1/10 G

    Has a 3/4" Zeal pad at each corner and is pushed down from above with soft foam.

    I am running 3.0 with inertial and had very solid Alt Hold and Loiter in 10mph gusts.

    May actually need to turn response in Loiter down a bit.

    Rate P = .08 Rate I = .05  and 40 percent expo on transmitter. Stabilize is very solid.


  • Ok now I have tried also connecting it, waiting 30 min, then starting missionplanner and trying to connect. Same result. Then I did the same except resetting and waiting instead, still same thing. Also tried different usb port, no change. 

    What I wonder is if it looks the way it should in device manager as I am out of ideas. This is what I see on my windows 7 box:


    I am starting to think the FMU may be defective as it doesn't work properly with PX4 standard firmware, and also not with arducopter firmware, although the behavior is wildly different. 

  • Gary, yep I am aware of the disconnect/reconnect. Just for testing purposes I also tried to leave usb plugged in without doing anything for about 25min before attempting to connect, but still no hartbeat. What I did not try was resetting it, will try that later today. 

    Should the LED's just be on constant without any kind of blinking? With the native PX4 it always has some form of blinking going on with different blink speeds/LED's depending on what it's doing. Didn't look at it in detail but that's my observation. 

  • Just a quick thought, you probably know this, but after uploading the firmware to the PX4FMU via Mission Planner you do need to disconnect the USB connection and then reconnect it.

    Then you need to wait at least 10 seconds, click on the Port Icon and make sure that the correct PX4FMU port is selected.

    And then select the "Connect" tab in order to have mission planner communicate with it.

    It might be necessary to hit the PX4's reset button and wait 10 seconds before "connecting", it shouldn't be, but sometimes it has been.

    I periodically do not get an immediate "connect" and MavLink download, usually I just unplug the PX4, plug it back in, wait 10 seconds and try and connect again.

    You do have to wait 10 seconds after the USB has been plugged in or the reset button has been pushed before you "connect".

    And you do need to ensure that the Port Icon shows that you are connected to the "PX4FMU" COM port.

  • tried both ArduCopter 2.9.1b as well as 3.0.0 rc1, firmware uploads fine but after that nothing, no hartbeat, so mavlink connecting is aborted...

    Since I am not familiar with MissionPlanner at all I have no clue if it is behaving correctly, at any rate when uploading the firmware the LED's blink on the FMU so that part seems to be doing what it should, but after reconnecting all I get is the bootloader red blinking and after that what looks like solid green and blue LED. They do not blink at all like with a configured PX4 normally. 

  • Tested now with the missionplanner download thingie, and I can apparently flash the firmware on the device but that's it. Mavlink fails to connect after 30sec of timeouts. So I tried it all from scratch again, same result after many attempts at unplug, wait, replug, wait click connect. 

    I am getting COM10 PX4 FMU v1.6(COM10) in the comport listing of MP so the port is def the right one, unless it now should say something else when I am using the MP etc.

    Any suggestions? The usb port works fine on it with it otherwise, just apparently not liking the missionplanner setup unless I have to uninstall the PX4FMU driver and replace it with something else. The MP installer did install some kind of drivers but I doubt they are being used. 

  • Oh to answer your question, yep using PX4 without any IO now as the AR drone thingie is dead atleast seems to be. I still think the px4 firmware has an issue with versions on the motors as I cannot see anything hardware wise atleast on PX4IOAR that even could be defective... But I do need to figure out if the FMU is working or not properly. 

  • Gary, the LED's on the FMU show armed state with the LED's, forget exactly which LED did what (disassembled/disconnected at the moment). At least they do with the standard PX4 firmware ver I am running on it atm. 

    What exactly do you mean by calibrating the ESC's? I have flown the same escs using the KK2 board so the ESCs are definitely fine and set up the same way. Or do you mean the setup you do in QGC? Done all the setup and calibrations there also. 

    Now going to try the mission planner install thing and see if that does something else VS what has been going on sofar with it, will be back with my findings. 

    Btw just to be sure, the arducopter firmware DOES work without GPS etc standalone also? 

  • Hi Noth666,

    My experience is with the PX4FMU plus the PX4IO and from what I can figure out you are running the PX4FMU without the PX4IO.

    I do know for a fact that other people have had success with that and if your system is working, you should be able to as well.

    From what you have said you could not get the motors to spin up even after it was armed.

    How do you know it was armed?

    On the PX4IO version, there is a "Safety Button" which must be pressed to get it to be able to arm, but it also has a LED in the top of it which indicates it is ready to be armed.

    I don't think the PX4FMU only has any such clear indication of being armed.

    On mine I sometimes need to go through the disarm (Throttle down and to the left) procedure before the Arm procedure will work.

    And at least one person has said on a PX4FMU only version that he needs to preform a board reset before he can arm.

    Are your ESCs calibrated?

    It doesn't seem to me you could have gone through the ESC calibration procedure because in it your motors have to spin up and it doesn't sound like yours ever have and if the ESCs aren't calibrated the motors will not turn.

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